Elevator control device

ABSTRACT

In an elevator system comprising a plurality of elevator cars each serving a plurality of floors, an elevator control device is provided in which each car has a service zone, hall calls within which the particular car is capable of answering, which service zone is changeable at any moment according to the changing traffic situation, any hall call generated from a floor being transmitted only to that car the service zone of which includes such a floor. Lest the service zone of a car includes so many floors that it is not certain whether or not the particular car is able to serve the farthest floor included in its service zone in a reasonable time, a maximum length or size of the service zone is predetermined thereby to prevent the car from answering a hall call from an extremely far floor.

United States Patent [191 Iwasaka et al.

[ ELEVATOR CONTROL DEVICE [75] Inventors: Tatsuo Iwasaka; Takeo Yuminaka;

Hideto Matsuzawa, all of Katsuta; Taiji Ishizuka, Tokyo, all of Japan [73] Assignee: Hitachi, Ltd., Tokyo, Japan [22] Filed: Apr. 18, 1973 [21] Appl. No.: 352,480

[30] Foreign Application Priority Data Apr. 19, 1972 Japan 47-38630 May 19, 1972 Japan 47-49073 May 26, 1972 Japan 47-51718 [52] US. Cl 187/29 R [51] Int. Cl B66b 1/18 [58] Field of Search 187/29 [56] References Cited UNITED STATES PATENTS 3,685,618 8/1972 Takahashi et al 187/29 3,729,066 4/1973 Iwasaka et a1. 187/29 Dec. 31, 1974 Primary Examiner-B. Dobeck Assistant ExaminerW. E. Duncanson, Jr. Attorney, Agent, or Firm-Craig & Antonelli 5 7 ABSTRACT In an elevator system comprising a plurality of elevator cars each serving a plurality of floors, an elevator control device is provided in which each car has a service zone, hall calls within which the particular car is capable of answering, which service zone is changeable at any moment according to the changing traffic situation, any hall call generated from a floor being transmitted only to that car the service zone of which includes such a floor. Lest the service zone of a car includes so many floors that it is not certain whether or not the particular car is able to serve the farthest floor included in its service zone in a reasonable time, a maximum length or size of the service zone is predetermined thereby to prevent the car from answering a hall call from an extremely far floor.

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SHEET 1 1 [1F 1 1 lNl I U INI UA| INz ELEVATOR CONTROL DEVICE The present invention relates to an elevator control device effectively applied to an elevator system including a multiplicity of elevator cars serving a multiplicity of floors.

In a conventional elevator control device, a hall call generated from a floor is transmitted to all of the multiplicity of cars and such a floor is served by a car which approaches the floor earlier than any other cars.

W Such aconventional device does not take intocon sideration the relationship between the multiplicity of cars and therefore it often happens that a plurality of cars run in a bunch at or in the vicinity of a floor. This offsets the advantages of availability of the multiplicity of cars in the same building, with the result that passengers at some floors have to wait relatively long time until a car arrives at their floors for their service.

Also, waiting passengers are not sure which of the cars is ready to serve their floors, making it necessary to watch the movement of all of the cars. Even though an arrival indicator is provided in the vicinity of the landing for each car to indicate that the car is to arrive at the landing soon, passengers waiting at the landing far from a landing on the same floor at which it is indicated that a car is to arrive soon may have to rush to the landing to catch the arriving car at the last moment, resulting in a congested situation in a hall.

One method to overcome the above-mentioned problem of the conventional control device for a multiplicity of cars may be to provide means for indicating to the waiting passengers earlier an expected arrival of a car.

In a device incorporating such a device, a service zone is allotted to each car which service zone is changed at each moment according to the changing traffic situation, and in addition there is provided at each floor a guide means for indicating a car expected to serve the floor. The term service zone as used in this specification means an area hall calls from which a car is able to answer. A floor from which a hall call is generated is included in one of the service zones of the cars, so that that hall call is transmitted only to that car the service zone of which includes such a floor, whereby the particular car to which the hall call is transmitted serves the'particular floor.

The service zone of each car includes an area from the floor at which the car is positioned to the floor at which the preceding car is positioned and is changed at each moment in accordance with the operating conditions of the cars.

A car which is expected to serve a particular floor from which a hall call is generated is determined at the time when the hall call is generated. Therefore, if that fact is indicated to waiting passengers by means of guide means, the waiting passengers do not have to take the trouble of watching all the cars, thereby eliminating the congested situation on each landing.

In this connection, when the preceding car is running far ahead, a car succeeding to that car has a large service zone. In such a case, a hall call generated from a floor in advance of the car is transmitted only to that car whose service includes the floor, and this results in a very long time being needed to serve the floor from which the hall call is generated. In such a situation, a car succeeding to the car with the large service zone has a very small service zone and may soon outrun the car, so that the succeeding car may reach the particular floor earlier than the car which answered the hall call from the floor, while the succeeding car to which no hall call from that floor has been transmitted passes that floor without responding to that hall call. For this reason, the waiting passengers have to wait for a long time until the arrival of the car which has a large service zone.

By allotting a service zone to each car. it is possible to inform waiting passengers eariler of the expected ar- 7 rival of a car, but the provision of the service zone as above is often accompanied by the disadvantage of a long time for which the passengers have to wait for a car. Further, if a car other than the car indicated by the guide means such as the succeeding car in the above case serves the particular floor in response to a cage call, the waiting passengers not only are confused but develop a disbelief in the guide means.

Accordingly, it is an object of the present invention to provide an elevator control device which is capable of improving the operating efficiency of an elevator system including a multiplicity of cars by shortening the average car waiting time.

Another object of the present invention is to provide an elevator control device with a reliable guide means, taking into consideration the necessity to inform waiting passengers of expected car arrival as soon as possible.

It is a feature of the present invention that the maximum size of the service zone of each car is limited thereby to prevent the car from answering a hall call generated from a floor beyond that limitation.

A second feature of the invention is that the maximum size of the service zone is adjusted in accordance with the operating condition of each car including the intervals between the cars and the number of hall calls generated.

The above and other objects, features and advantages will be made apparent by the detailed description taken in conjunction with the accompanying drawings, in which:

FIG. I is a diagram for explaining the operation of elevator cars A, B and C as an example serving a 10- storied building and employing the elevator control device according to the present invention;

FIG. 2 is a diagram showing a circuit for detecting the spatial interval between car A of FIG. I and the succeeding car, a like means being provided for every car;

FIG. 3 is a diagram showing a circuit for detecting the number of hall calls to be answered by car A according to the present invention;

FIG. 4 is a diagram showing a circuit for counting the number of average hall calls to be answered by cars A to C;

FIG. 5 is a diagram showing a circuit for generating reference voltages used in comparators for the circuit of FIG. 6;

FIG. 6 is a diagram showing a circuit for determining the time interval for car A, a like circuit being provided for each car;

FIG. 7 is a diagram showing a circuit for making a decision on whether or not to answer a hall call for car A, a like circuit being provided for each car;

FIG. 8 is a diagram showing a circuit for interlocking the circuits after it is determined which car is to answer a hall call;

FIG. 9 is a diagram showing a circuit for determining the priority in which the cars are required to answer a hall call;

FIG. 10 is a diagram showing a circuit for driving a guide means for car A, a like circuit being provided for each car;

FIG. 11 is a diagram showing a guide means for informing waiting passengers that car A is ready to serve them, a like means being provided for each car;

FIG. 12 is a diagram showing a circuit corresponding to the circuit of FIG. 7 for another embodiment of the invention;

FIG. 13 is a diagram showing a circuit corresponding to the circuit of FIG. 7 for still another embodiment of the invention;

FIG. 14 is a diagram showing a circuit for detecting the operating condition of car A by means of the load in its cage according to an embodiment of the invention, a like circuit being provided for each car;

FIG. 15 is a diagram showing a circuit for detecting the number of hall calls from each of the four areas ZCl to ZC4 in another embodiment of the invention into which the 10 floors of the building are divided;

FIG. 16 is a diagram showing a circuit for calculating the number of average hall calls from each floor in the embodiment of FIG. 15;

FIG. 17 is a diagram showing a circuit for detecting the traffic demand of area ZCl in the embodiment of FIG. 15, a like circuit being provided for each area;

FIG. 18 is a diagram showing a circuit for limiting the service zone of car A in area ZCl in the embodiment of FIG. 15, a like circuit being provided for each car; and

FIG. 19 is a diagram showing a circuit corresponding to the circuit of FIG. 7 for making a decision on whether or not to answer a hall call for car A in the embodiment of FIG. 15, a like circuit being provided for each car.

In an elevator system comprising a plurality of elevator cars, it is necessary to control the operation of the cars efficiently while relating them to each other systematically. For this purpose, the elevator system is so arranged that each car has its own service zone taking into consideration'the operating conditions of the other cars, a floor from which a hall call is originated is included in one of the service zones of the cars, so that such a hall call is transmitted only to the car involved. In other words, a car which is most suitable to serve a hall call is designated at each time of the generation of the hall call.

In FIG. I, for example, assume that cars A, B and C are designed to serve a l0-storied building. Car A has a service zone including the area including the second floor up to the 10th floor down as indicated by arrow. In like manner, cars B and C have their service zones as indicated by arrows respectively. Under this condition, when an up hall call'is generated from the 8th floor, such a hall call is transmitted only to car A whose service zone includes the 8th floor up, whereby car A answers the hall call to serve the 8th floor for upward movement. This prevents to some degree a plurality of cars from answering a hall call or a plurality of cars from running in a bunch at or in the vicinity of a floor.

Also, by allotting a service zone to each car, a car which is required to answer a hall call is determined at an early time, and therefore it is possible to inform waiting passengers which of the cars is to serve them in advance.

However, the determining of the service zones as shown in FIG. 1 covering the length from the position of a car to that of a preceding car has the disadvantage that a car or two occupy most of the floor as their service zones in some operating conditions, resulting in an undesirable situation where such a car or two answer most of hall calls generated. In such a case, it takes much time for a car to serve the farthest floor of its service zone, requiring passengers to wait for a long time on the landing of that floor. In the operating state of FIG. 1, for example, car A answers a down hall call that may be issued from the 10th floor. Since car A is required to serve hall calls from the second to 9th floors for upward movement, too, the succeeding car B may outrun car A by the time car A arrives at the 10th floor for down service. In spite of that, car B passes the 10th floor without stopping there since it has not answered the hall call from the 10th floor. For this reason, the passengers waiting at the 10th floor for downward movement must experience great inconvenience in awaiting the arrival of car A for a long time.

In order to obviate the above-described inconvenience, the present invention is intended to provide means for determining the maximum size of the service zone of each car by limiting the forward extent of the service zone and thus preventing the answering of hall calls from far floors.

Prior to entering the detailed description of the device of the invention, explanation will be made of certain terms used in the specification.

The interval means a spatial interval between actual physical positions of two elevator cars or a time interval therebetween determined on the basis of the number of floors expected to be served by one of the cars running behind the other and/or a combination of a spatial interval and a time interval.

The position signal means a signal indicating a physical position represented by the floor number where a particular car is located or the distance from a certain reference, or in the case of a running car, a floor number in advance of the physical position of the car. Assume, for example, that a car is running up at the third floor. Then, its position signal may indicate that 4th floor, 5th floor or 6th floor depending on whether it is running at low, medium or high speed respectively.

The present invention will be now explained in detail with reference to the accompanying drawings. For convenience of explanation, it is assumed that a lO-storied building is served by three cars A, B and C.

A circuit for detecting the spatial interval between car A and a succeeding car is shown in FIG. 2. In the figure, reference symbols F lUA to F9UA show position signals issued when car A is moving up at the first to 9th floors respectively, symbols F2DA to FIODA position signals produced when car A is moving down at the second to 10th floor respectively, symbols FlUB to F9UB position signals produced when car B is moving up at the respective floors, symbols FZDB t0 FIODB position signals produced when car B is moving down at the respective floors, symbols FZDC to Fl0DC position signals produced when car C is moving down at the respective floors, symbols OlUAl to O9UA2 and O2DA1 to OlODA2 OR elements, symbols IlUA to I9'UA and I2DA to ll0DA inhibit elements, r and r resistors, and symbols da a signal indicating the spatial interval between car A and a succeeding car.

As shown in the drawing, the elevator service floors are connected endlessly in the loop FlUF2D-F3D F9D-Fl0DF9U-F8U F2U-FIU, through which the position signal for car A is sent until it is cut off by the position signals for car B or car C. In the meantime, the signal da indicating the spatial interval is obtained through the resistors r r Let us consider a case, for example, where car A is moving up at the 8th floor, car B moving up at the second floor and car C is moving down at the th fioor, in which case a car succeeding to car A is car B. The position signal F8UA for car A is transmitted through the loop F8UA-O8UA1I I8UA-O7UA1 I3UAO2UAl-I2UA. The position signal F2UB for car B, however, is in the state of l and therefore the inhibit element IZUA is in an inhibited state through the loop F2UB-O2UA2I2UA. As a result, the output signal of the inhibit element I2UA is 0, preventing the signal from being applied to the following stages.

It will be noted from the above description that the output signals of inhibit elements I8UA, I7UA, I4UA and I3UA are l and so a signal indicating the 6th floor is produced across the resistor r through the resistor r which constitutes the signal da. At the same time, a signal in proportion to the number of the floors is produced across the resistor r if r r A circuit for detecting the number of hall calls to be answered by car A is shown in FIG. 3, in which reference symbols RylUAZ to Ry9UA2, Ry2DA2 to Ryltl- DA2 denote signals for stopping car A which are produced when the relays RylUA to Ry9UA and Ry2DA to RyltlDA of FIG. 10 are energized respectively. As in FIG. 2, voltage CA proportional to the number of hall calls is produced through the resistors r and r By means of the circuit of FIG. 4, the number of hall calls for all the cars are added to each other to calculate an average number of hall calls for each car. Symbols CA to CC show the numbers of ball calls to be answered by cars A to C respectively which are obtained in the manner shown in FIG. 3, symbols NoAl, NoA2, NoBl, N0B2, NoCl and N0C2 relay contacts which are opened when cars A to C are put out of controlled operation respectively, symbol R an operational resistor, and symbol 0P1 an operational amplifier for reversing the polarities of input and output.

Assume now that cars A to C are in controlled operation. All of the contacts NoAl, 2 to NoCl, 2 are closed. Under this condition, call inputs for cars A to C are assumed to be CA, CB and CC respectively. Then, the output C of the operational amplifier is Also, it is assumed that car A is put out of controlled operation. Then,

From this equation, it will be understood that the output C of the operational amplifier takes a value equal to an average number of hall calls to be answered by each car.

A circuit for obtaining reference voltages for the comparators of FIG. 6 is shown in FIG. 5. In this figure, the contacts NoA3 to NoC3 are opened when cars A to C are in controlled operation respectively. Therefore, the output of the operational amplifier OP2 is given as 0P2 4/ 3) (R4/R3) V In this equation, it is assumed that V 6V by appropriately selecting the values of resistors R R and R In the event that car A is put out of controlled operation, the contact N0A3 is closed and therefore the output voltage of the operational amplifier 0P2 is expressed as l/R 2. In this equation, the relation V 10 V is obtained by properly selecting the value of resistor R The output of the operational amplifier is divided properly by the variable resistors R and R thereby to produce reference voltages V, and V As mentioned above, it is possible to obtain the outputs V and V of 5 and 4 volts respectively when V =6V, while they are 8.3 and 6.6 volts respectively when Vopz 10 V.

A circuit of FIG. 6 is provided for determining the time interval for car A depending on the operating condition thereof, to which the outputs from the circuits of FIGS. 2 to 5 are applied. In the circuit of FIG. 6, reference numerals OPAl to OPA2 show operational amplifiers, CMAI and CMA2 comparators which produce the output of 1 when the sum of the inputs thereto is zero or positive, NA a NOT element, II-I an inhibit element, EOA to EZA instructions to advance provisionally the position of car A by zero floor, one floor and two floors respectively in accordance with the time interval thereof.

The number CA of hall calls to be answered by car A which is obtained by the circuit of FIG. 3 is added to the average number of ball calls obtained from the circuit of FIG. 4 in the operational amplifier OPAl thereby to obtain the output of the operational amplifier OPAI shown by the equation VOPA2 (CA+C) CA /3 (CA+CB+CC) 3. In like manner, the output of the operational amplifier OPA2 is expressed as omz a 7 VOPAI a a da 4- By appropriately selecting the ratio of the value of resistor R A to that of R A, it is possible that I V represents the spatial interval of one floor and approximately 3 V one hall call. In other words, by properly balancing between the interval and number of hall calls, it is possible to obtain the time interval of a car. Equation (4) is alternatively expressed as K,C(K,/3)(CA+CB+CC)K -da 5. From this equation, it is apparent if the number of hall calls to be answered is equal to the average number of hall calls, the first and second terms in equation (5) are the same, so that V =-I da. If the number of hall calls to be answered by car A is greater than the average number of hall calls by one, on the other hand, the relation K CA (K /3) (CA'l-CB+CC) +3V results. When the number of hall calls to be answered by car A is less than the average number of hall calls, the relation K CA (K /3) (CA+CB+CC) -3 V is obtained. It is apparent from above that the operating condition of car A is obtained in the form of time interval thereof taking into consideration the spatial interval and the number of hall calls thereof.

It is assumed here that the spatial interval between car A and the succeeding car is 6 floors which is more than the average number of hall calls by one. The relation VOPAZ +3 V 6 V=3 V results. If the reference voltages V and V for the comparators CMAI and CMA2 are 5 V and 4 V respectively, the comparator CMAI produces an output of 1 upon application thereto of the inputs of -3 V and 5 V, while on the other hand the comparator CMA2 generates an output of I on receipt of the inputs of 3 V and 4 V. As a result, the signal E2A is turned to l the output of the inhibit element [H is prevented and the NOT element NA produces an output of since it receives an input of 1".

If VOPAQ 5 V, the inputs of 5 V and 5 V are applied to the comparator CMAI and therefore it produces an output of I, while the comparator CMA2 produces an output of 0 upon receipt of -5 V and 4 V. Thus the comparators CMAl and CMA2 determine the time interval for each car depending on the operat ing condition thereof and produces signals EOA to E2A as required.

A circuit for deciding on whether or not to answer a hall call on the basis of the position signal for car A and the signal representing the time interval of car A is shown in FIG. 7. A circuit for interlocking the circuits after the determination as to which of the cars to answer the hall call is illustrated in FIG. 8, while the circuit of FIG. 9 determines the priority in which the cars are to answer the hall call. In the figures, reference symbols AlUAl to A9UA4 and A2DA1 to ADA4 show AND elements, symbols 01UA3 to 09UA8 and 02DA3 to 010DA8 OR elements, INlUAl to IN9UA4 and IN2DAI to IN10DA4 inhibit elements, symbols 1U to 9U and 2D to 10D the output signals produced from the circuits comprising the OR elements as shown in FIG. 9, symbols MlU to M9U and M2D to MIOD the output signals produced from the circuits shown in FIG. 8 respectively, symbols I-IClU to HC9U and I-IC2D to HClOD signals representing up hall calls from the first to 9th floors and down hall calls from the second to 10th floors respectively, symbols LlUA to L9UA and L2DA to LIODA signals for energizing the guide lamps connected to the circuit of FIG. 9, and symbols ClUA to C9UA and CZDA to ClODA signals representing up cage calls from car A for the first to 9th floors and down cage calls from car A for the second to 10th floors respectively.

In the above-mentioned circuit arrangement, it is assumed that car A is moving up at the second floor and car B preceding to car A is moving down at the 10th floor, while time interval signal E0 is produced for both cars A and B. It is also assumed that car C is moving down at the fifth floor,

The fact that car A is located at the second floor and that time interval signal EOA is 1 causes the AND element AZUAl to produce a 1 signal which is applied through the OR elements 02UA3-02UA5- IN- 2UA2IN2UA3.

Also, a signal from 02UA5-IN2UA5 is applied to the inhibit element INJUAI for the 3rd floor (not shown) and then to like elements from the 4th to 7th floors. The signal from the 7th floor is applied as an input to the inhibit element IN8UA1 and then through IN8UAlO8UA5IN8UA2-IN9UA1 9UA5-IN9UA2-IN10DA1. On the other hand, the signal from the OR element 02UA3 is applied to the OR element 02UA4 which makes up signal 2U through the circuit shown in FIG. 9. The output from the OR element 02UA3 constitutes the only input to the OR element 02UA4 for car A, while the OR elements 02UB4 and 02UC4 for cars B and C receive respectively the two inputs from OR elements 02UB3 and 02UC4 and from OR elements 02UA4 and 02UB4. In this way, the priority is determined in which a hall call is answered by a plurality of cars, if any, which may be located at the same floor.

The output of 02UA4 is applied to the OR element 02UB4 and the inhibit element IN2UB2, while the out put of the OR element 02UB4 is applied to 02UC4 and IN2UC2 for car C, so that car A, B or C is required to answer the hall call in that order of priority. On the other hand, the output from the OR element 02UC4 makes up the signal 2U which is applied to the inhibit elements IN2UA1, IN2UBI and INZUCI to prevent the output therefrom.

It will be noted from the above explanation that the I 1 signal from the OR element 2UA3 for car A becomes signal 2U, which is used to prevent the energization of the circuits for answering a hall call for cars A, B and C. Under this condition, the input to the inhibit element IN2UC1 for car C is prevented thereby to produce a 0 output.

In like manner, the fact that car B is located at the 10th floor causes the signal IOU to be put into the state of l whereby the output of the inhibit element INI- J. isprsv ntqdt erw to P 9 a Output therefrom. As a result, the outputs of the inhibit element IN3UA3 to IN9UA3 for car A are put into the state of 1 thereby to define the service zone for car A under such a condition.

Assume now that cars A and B are located at the second floor for upward movement, while car C is moving down at the 10th floor. In such a case, it will be easily understood from the above explanation that the OR elements 02UA3 and 02UB3 produce l outputs. As is apparent from the circuit of FIG. 9, however, the l signal from the OR element 02UA3 for car A is applied through 02UA4 to IN2UB2 thereby to prevent the output of the inhibit element IN2UB2. As a result, the output of the OR element O2UB4 for car B is prevented thereby to prevent the signal from being applied to the following stages.

As can be seen from above, in case two or more cars are located at the same floor, a hall call is answered by car A, B or C in that order of priority.

This priority of order must take into consideration the order in which the cars are required to start in the case of the first floor, in which case the car starting first may be given the top priority.

The above explanation refers to the case in which time interval signal EOA isproduced, that is to say, the number of hall calls to be answered by car A is greater than the average number of hall calls and also there is a great interval between car A and the succeeding car. If many hall calls for car A are issued under the condition as shown in FIG. 1, however, the time interval determining circuit produces output E2A, so that the AND element A4UA3 of the circuit of FIG. 6 produces a 1 signal, whereby the OR element 04UA3 also produces a l signal (not shown). In other words, in spite of the fact that car A is actually located at the second floor, its provisional position is determined as the 4th floor thereby to determine the service zone for car A. It will be thus seen that the service zone of car A includes the 4th floor up to the IOth floor down, while the succeeding car has the service zone of the second floor down to the third floor up. In this way, efficient service to the waiting passengers by each car is achieved by setting a provisional position of each car in addition to its actual position depending upon the operating condition of the whole system.

As explained above, the interval between each car and'the other cars and the number of hall calls to be answered by each car are detected and compared with each other, whereby each car is systematically related to the other cars to achieve efficient operation of the elevator system.

Referring to FIG. ll, even if the position of car A is provisionally advanced to the 4th floor up, car A is required to answer any hall calls which may have been issued from the second or third floor, a will be explained more in detail later. In such a case, if car C has a small number of hall calls to be answered, it may soon outrun car A. As a result, it is uncertain which of the cars will first arrive at the 9th floor for upward service or at the th floor for downward service. In the prior art system, it is determined that car A should serve the 9th or 10th floor as soon as hall calls are produced from them for upward or downward service respectively in the operating state of FIG. I.

In order to obviate such disadvantages, the size of service zone of each car is limited by various means.

Assume that each car is positioned as shown in FIG. 1 d. time nter aLasna sEQA t I392. areprqriasssi for the cars respectively. The inhibit elements IN2UA3 to IN9UA3 in the circuit shown in FIG. 7 tend to produce l signals to determine the service zone of car A. However, the position signal FZUA is further applied to the inhibit element IN9UA4, and the output of the inhibit element ln9UAl is prevented by the signal applied thereto through IN9UA2 is prevented by the signal applied thereto through IN9UA4, II9UA8 and IN9UA1I, thus preventing the signal produced by the inhibit element IN8UA2 from being applied to the following stages. As a result, the service zone of car A is determined as the second floor up to the 8th floor up. In this way, the service zone is limited to the maximum number of floors of 7, so that it is not determined or it is left uncertain which of the cars is to serve the 9th floor for upward movement. With the arrival of car A at the third floor for upward service, the 9th floor for upward movement is included in the service zone of car A. At that time, even if car B is located at the 8th floor for downward service, neither the Itlth floor down nor the 9th floor down is included in the service zone of any car.

Also, it will be apparent that under the condition shown in FIG. II the service zone of car A is the third floor up to the 8th floor up or the 4th floor up to 8th floor up when time interval signal IZIA or F.2A is produced respectively for car A.

Reference symbol PT shows means for lifting the lim-- itations set as above by application of a l signal when the number of service cars is reduced, resulting in an increased size of service zone for each car. The operation of such means will be apparent.

The output signals LIUA to L9UA and LZDA to LIIIDA from the circuit of FIG. 7 are applied to the circuit of FIG. It), thereby engergizing the relays RyIUA to RySlUA and RyZDA to RyItIDA through the selfholding amplifier elements RIUA to R9UA and R2DA to RIIODA respectively. Also, the guide lamps SIIUA to S9UA and SZDA to SIIODA provided for each floor as shown in FIG. II are turned on by the relays.

It is assumed that an up hall call is generated from the 8th floor when the service zone from the second floor up to the 9th floor down is allotted to car A. In FIG. 7, the hall call signal I-IC3U for upward movement from the 8th floor in FIG. 7 is turned to I, and therefore the two inputs to the AND element A8UA4 for car A are put into the state of I resulting in a 1 signal being produced therefrom. This signal is applied to the OR element tlfiUAb to turn the signal L8DA into the state of l. The signal L8DA is applied to the selfholding amplifier element R8UA in the guide means driving circuit of FIG. 10 thereby to energize the relay Ry8UA. The energization of relay RyfiUA causes the guide lamp SSUA of FIG. to be turned on, thereby informing the waiting passengers at the 8th floor for upward service of the expected arrival of car A at the floor. Similar guide lamps SllUA to S9UA to SIODA are provided for the respective floors. In other words, the waiting passengers at the landing are informed in advance of the actual arrival time of car A that car A is ready to serve the floor.

With the energization of the relay Ry8UA, the signal RyfiUAll of FIG. 8 is turned to l whereby the output signal M8U of the OR element (WU becomes also l This signal M8U is applied to the inhibit elements IN- 8UA3, IN8UB3 and IN8UC3 of FIG. 7 to prevent the outputs thereof. As a result, the signal LSUA for car A becomes 0". Since the self-holding amplifier element R8UA of FIG. I0 memorizes the fact that car A has answered the up hall call from the 8th floor, however, the guide lamp ShUA continues to be turned on, with the result that it is determined that car A serves the hall call from the 8th floor for upward movement, while at the same time interlocking the circuits to prevent the other cars from answering the hall call.

As a result of the energization of relay RyhUA, the signal RyfiUAZ in the state of l is produced from the circuit for detecting the number of hall calls to be answered by car A shown in FIG. 3.

Since a cage call is required to be answered without regard to the service zone, the production of an up cage call C9UA for the 9th floor, for example, to be served by car A causes the OR element 9UA6 of FIG. 7 to produce a I output, while the signal L9UA becomes l so that the guide lamp S9UA is turned on as in the previous case. Also, the inhibit elements IN9UA3, IN- 9UB3 and IN9UC3 are prevented from producing their outputs in such a manner that even if another up hall call is generated from the 9th floor, no car answers that call. Inconvenience may results from the fact that a cage call is registered unconditionally regardless of the service zone. and therefore an arrangement can be made in which a cage call may not be talten into consideration by eliminating the OR elements ()IUAh to (WU/W and OZDAfi to tIItllIlDAb of FIG.7.

Under this condition, when car A'arrives at a deceleration point to stop at the hth floor for upward service,

ill

a deceleration command is issued thereby to control the circuits to stop car A at the 8th floor through a control means (not shown). As a result, the signal SDSUA of FIG. 10 is turned to l thereby releasing the selfholding amplifier element R8UA from its self-held state.

In the above-described embodiment of the invention, forward extension of the service cone is limited to define the service zone within an appropriate size. For this purpose, the position signals FlUA to F9UA and F2DA to F10DA for car A are applied to inhibit elements INlUAI to IN9UA1 and IN2DA1 to IN10DA1 as inhibiting signals through the inhibit elements IN- 1UA4 to IN9UA4 and IN2DA4 to IN10DA4 respec tively. In this way, the size of service zone for each car is limited to 7 floors under any operating conditions.

A circuit for deciding on whether or not to answer a hall call for car A according to another embodiment of the invention is shown in FIG. 12, said circuit corresponding to the circuit of FIG. 7 for the preceding embodiment.

In the embodiment of FIG. 12, the purpose of limiting forward extent of the service zone is achieved by applying to the inhibit elements INIUA4 to IN9UA4 and IN2DA4 to lNlDA4 the provisional position signals f1 UA to f9UA and f2DA to fl0DA for car A which are the outputs from the OR elements O1UA3 to O9UA3 and O2DA3 to Ol0DA3, the other arrangement being quite the same as in the circuit of FIG. 7.

Assume, for example, that car A is located at the second floor for upward service and no other car is taken into consideration. If the time interval signal EOA,E1A or E2A is produced, the service zone for car A includes the second floor up to the 8th floor down, the third floor up to the 9th floor up and the 4th floor up to the 10th floor down, respectively. It will be apparent that the size of service zone is thus limited to 7 floors.

A circuit corresponding to the circuit of FIG. 7 according to another embodiment of the invention is shown in FIG. 13.

The circuit of FIG. 13 is further provided with a service zone setting circuit C thereby to set the maximum size of the service zone for each car as desired depending upon the operating condition of each car. Differing from the above explanation taking into consideration a cage call, the explanation below disregards a cage call by eliminating the OR elements 01UA6 to 09UA6 and 02DA6 to 010DA6 of FIG. 6.

A day may be divided into the four periods of time, i.e. morning rush hours, evening rush hours, intermediate hours and lunch time in accordance with the traffic demand. During the morning rush hours, demand is high for up service, while there are many down hall calls during the evening rush hours. Also, if a cafeteria is situated at the 8th floor, there will be great demand for upward movement to the 8th floor during the lunch time. Further, when meetings or conventions are held, there will be heavy demand for car service to that floor where there is a hall for the meeting.

In such cases, if satisfactory car service is to be offered, it is necessary to change the maximum size of service zone for each ear in accordance with the prevailing traffic demand.

For this purpose, the output from the service zone setting device C is applied to the inhibit elements IN- lUA4 to IN9UA4 and IN2DA4 to lNl0DA4, while either the position signals FlUA to F9UA and F2DA to FIODA or provisional position signals fl UA to f9UA and f2DA to flODA as shown in FIG. 12 are applied to the service zone setting device C.

The operation of the service zone setting device C will be now explained below.

The relations between the input and output are determined as shown in Table l, as an example. One of the switch signals S1 to S5 is applied to the service zone setting device in accordance with the traffic demand, whereupon the service zone setting device produces the outputs BlU to B9U and 82D to BIOD, corresponding to the switch signal applied thereto, in response to the input position signals FIUA to F9UA and F2DA to FlODA.

If the switch signal S1 is produced when car A is located at the second floor for upward service, signal B7U is produced from the service zone setting device C, and the output of the inhibit element IN7UAI is prevented through B7UIN7UA4O7UA6IN7UAI (not shown), thereby limiting the forward end of the service zone for car A to the 6th floor up. When car A moves up to the third floor for further upward service at the next moment, signal B8U is produced thereby to prevent the output of the inhibit element IN8UA1. In this way, signals BlU to B9U and 82D to BIOD are produced in response to the position signals FlUA to F9UA and F2DA to FIODA respectively thereby to limit the service zone for car A as required.

The maximum sizes of service zone determined by switch signals S1, S2 and S3 are 5, 6 and 7 floors respectively. When traffic demand is heavy, the service zone is limited by switch signal S1, while switch signal S2 may be used to limit the service zone during the hours of small traffic demand.

When demand for up service is heavy as during the morning rush hours, switch signal S4 is effectively used whereby the maximum size of service zone for upward movement is made small while that for downward travel is enlarged.

During the lunch time when demand for travel say, to the 8th floor where a cafeteria is situated is heavy, switch signal S5 is advantageously used to lessening the service zones for cars directed to the 8th floor while enlarging the service zone for those cars which travel in the other direction.

It will be easily understood that a variety of service zones may be set by the use of the switch signals to accomplish superior car service in a building provided with a plurality of elevator cars in accordance with the prevailing traffic situation.

Detailed description of the service zone setting device will not be made here since it is apparent to those in the art that such a device is produced easily with conventional means such as a diode matrix.

In actual operation, a car manager may select a signal out of the four switch signals S1 to S4 depending on the situations. Instead, transfer from one switch signal to another may be accomplished automatically with a time switch in the beginning of morning rush hours, evening rush hours, and lunch time.

Further, the size of service zone at which the service zone setting device is set is changed as desired for each car, and also switch signals SI to S4 can be used either commonly or separately for each car.

In addition, the switch signals S1 to S3 may be used in relation to the time interval signals EZAtoEOAd etermined on the basis of the operating condition of each car, thereby to effect the controlling of the service zones.

If demand for car A is greater than a predetermined reference level V and signal EZA is produced, it means that there are many calls for car A to be answered or that the succeeding car approaches closely car A. Thus, car A is advanced in its provisional position by time interval signal E2A, while at the same time the maximum size of service zone for car A is lessened with application of signal S1. If the number of hall calls for car A is smaller or the interval between car A and the succeeding car shorter, time interval signal EIA is produced for car A, whereby switchsignal S2 extends the far end of the service zone by one floor.

As can be seen from above, the maximum size of service zone for each car is determined by the use of time interval signals EZA tolIOA ofFIG. 6 in accordance with the operating condition which undergoes a change at each moment.

A circuit for determining and selecting one of the switch signals Sl to S3 according to another embodiment is shown in FIG. 14.

In the circuit of FIG. 6, the operating condition of each car is detected on the basis of the interval between car A and the succeeding car and also the number of calls to be answered by car A. In the circuit of FIG. 14, by contrast, the operating condition of each car is detected on the basis of the weight of the load in the car i.e. the net load.

In FIG. M, reference symbol WA shows means for detecting the load in car A, symbols CWAI and CWA2 comparators, symbol NWA a NOT element and symbol IWA an inhibit element, which operate in the same way as the comparators CMAI and CMA2, the NOT element NA and the inhibit element III of FIG. 6 respectively.

It is assumed here that the maximum limit of load allowed for car A is 300 kg, that the load detector WA produces a voltage proportional to the actual load of car A, and that the reference voltages V, and V of the comparators represent 100 kg and 200 kg respectively.

When the total weight of passengers in car A is less than [00 kg, a voltage proportional to the actual load is generated from the load detector WA and is applied to the comparators CWAl and CWA2. Since this voltage is lower than the reference voltages V, and V the outputs of the comparators CWAI and CWA2 are turned to l while at the same time only signal S3 is produced through the NOT element NWA. When there are so many passengers riding in car A that the load thereof exceeds 200 kg, the load detector WA produces a larger output than the reference voltage V or V whereby 1 signals are produced from the comparators CWAI and CWAZ, with the result that signal 81 is turned to 1 while both signals S2 and S3 become 0.

By using the signals $11 to S3 mentioned above as the switch signals for the service zone setting device C of FIG. l3, it is possible to lessen or enlarge the maximum size of the service zone of each car depending on whether there is many or few passengers in the car. In other words, the operating condition of the car is detected by its load condition thereby to determine the maximum size of service zone thereof.

It will be apparent from the above description that according to the present invention the maximum size of service zone is determined as required in accordance with the operating condition of the particular car.

The diagrams of FIGS. I5 to I9 show still another embodiment of the invention characterized in that the maximum size of the service zone is determinded for each car by limiting the forward extension thereof.

In the embodiment under consideration, the floors to be served by the cars are divided into four parts in such a manner that the first floor up to the 5th floor up is named the first area, the 6th floor up to the 9th floor up the second area, the llllth floor down to the 6th floor down the third area" and the 5th floor down to the second floor down the dth area". Traffic demand of each area is detected by the number of hall calls issued, in order to determine the maximum size of service zone for each car.

In the drawings, reference numerals I-IClU to HC9U and I-ICZD to lICllllD show hall call signals for upward service of from the first to 9th floors and downward service of from the second to lltlth floor respectively; symbols r and r resistors; R R and R operational resistors; symbols OPIZ and OPZZ operational amplifiers; symbols ClVlllZll and ClVIllZZ comparators; symbols NllZll to N123 NOT elements; symbols 012 and symbols OdUAd to OIIIDA6 OR elements; and symbols A4UA5 to AlltlDA'l AND elements.

A circuit for detecting the traffic demand of each area on the basis of the number of hall calls issued therefrom is shown in FIG. 15. As in the circuits of FIG. 3, signals ZCll to 2C4! are obtained by applying hall call signals I'ICIIU to I-IC9U and IICZD to PICWD in the manner shown.

The circuit of FIG. I6 which operates in the same manner as the circuit of FIG. a is provided for the purpose of calculating the average value CZ of traffic demand of all the areas upon receipt of the signals CI to 2C4 from the circuit of FIG. 115.

The diagram of FIG. I7 shows a circuit to determine the traffic situation of the first area by comparing signal ZC I from the circuit of FIG. l5 for the first area with the value CZ representing the average demand, similar circuits being required for the other areas. As an example, when the traffic demand ZCll of the first area is equal to the average demand CZ of all the cars, the sum of inputs to the operational amplifier OPZZ is zero and also its output is zero.

For the embodiment under consideration, reference voltages V and V are set at the levels corresponding to one and two hall calls respectively. When the output of the operational amplifier OP2 is zero, the comparators CMlZl and CM1Z2 both produce 1 outputs since the sum of inputs to each comparator is positive. Also, the NOT elements NIZ2 and NIZ3 produce outputs, while a l output is produced from the NOT element NlZl. As a result, only the traffic condition signal 121 is in the state of 1 while the other signals 122 and 123 are 0.

If the traffic demand ZCl of the first area is smaller than the average value CZ, the operational amplifier OP2Z produces a positive output, so that only the traffic demand signal 1Z1 becomes 1. When the traffic demand ZCl of the first area exceeds the average value CZ, the operational amplifier OP2Z produces a negative output. In such a case, if the demand of the first area is larger than the average by two calls, the sum of the inputs to the comparator CMlZl is 0 and its output is l with the result that the traffic demand signal 123 in the state of 0 is produced. When the demand of the first area is larger than the average by 3 calls, the comparators CMlZl and CM1Z2 both produce 0 outputs, while the traffic demand signals 122 and 123 become 1 and 1Z1 0.

Explanation will be made now of how the service zone for car A is limited in and around the first area by the circuit of FIG. 18 which receives the traffic demand signals 1Z1 to 123 for the first area and signals 221 to 223, 321 to 3Z3 and 421 to 423 and the position signals FlUA to F9UA and F2DA to FDA for car A. It is apparent that similar circuits may be used to limit the service zone for the other cars.

In FIG. 18, it is assumed that the traffic demand of the-first area is smaller than the average traffic demand, where demand signal 121 is produced. Under this condition, if car A is located at the second floor for upward movement, the AND element A9UA5 is in the state of l so that the limit signal G9UA is produced through the OR element O9UA6.

Let us consider another case in which the traffic demand signal 1Z2 for the first area is produced while car A is located at the second floor for upward service. The AND element A8UA6 produces a 1 signal, whereupon the limit signal GSUA is produced through the OR element O8UA6. In still another case where car A is located at the second floor for upward movement with the demand signal 123 being produced for the first area, the AND element A7UA7 produces a 1 signal and the limit signal G7UA is produced through the OR elements O7UA6.

The limit signals GlUA to G9UA and G2DA to GIODA thus obtained are applied to the inhibit elements INlUAl to IN9UA1 and IN2DA1 to INIODAI respectively of the circuit of FIG. 19 which corresponds to the circuit of FIG. 7, thereby to prevent their outputs. In this way, the forward extension of the service zone of a car located in a particular area is limited in accordance with the traffic situation of that area.

Assume, for example, that car A is located at the second floor for upward service and car B ahead of car A is located at the 10th floor for down service. In this case, it is also assumed that time interval signals EOA and E08 are produced for both the cars frorn the circuit of FIG. 6, that the traffic demand of the first area is smaller than the-average demand, that only the demand signal 12] is in the state of l out of the traffic demand signals obtained from the circuit of FIG. 16,

and that car C is at the 5th floor for downward service.

The AND element A2UA1 of FIG. 19 is put into the state of 1 which signal is applied through the OR elements O2UA3, O2UA5, and inhibit elements IN2UA2 and IN2UA3. As mentioned already, the signal from the inhibit element IN2UA2 is applied to similar elements for the third to 8th floors in sequence. while the signal from the inhibit element for the 8th floor is further applied to the inhibit element IN9UAI and then to IN9UA2 and INIODAI in that order. Since car 8 is located at the 10th floor for down movement, signal IOD is produced from a circuit for the 10th floor similar to the circuit of FIG. 9. This signal 10D is applied to the OR element O10DA6 of FIG. 18, wherefrom limit signal GlODA is produced thereby to prevent the output of the inhibit element INIODAl, thus preventing the signal from being applied to the following stages. As a result, the service zone of car A is determined as the second floor up to the 9th floor up.

The fact that the traffic demand signal 121 is produced for the'first area and that car A is located at the second floor for upward service causes the AND element A9UA5 of FIG. 18 to produce a l signal, while at the same time the limit signal G9UA is produced through the OR element O9UA6. This signal G9UA is applied to the inhibit element IN9UA1 to prevent the output therefrom, so that no signal from the inhibit element IN8UA2 is applied to the following stages. As a consequence, the above-mentioned service Zone of the second floor up to the 9th floor up is changed actually to cover the second floor up to the 9th floor up with the forward extension thereof limited, resulting in the maximum size of service zone being 7 floors.

Although the above description refers to the case in which the traffic demand signals 1Z1 to 423 are produced as required by the circuits of FIGS. 15 to 17, it is already mentioned with reference to FIG. 13 that a day may be divided into several predetermined periods of time such as morning rush hours, intermediate hours, lunch time and the like as shown in Table 2 below in accordance with the traffic condition of each area in order to adjust the service zone of each area as desired. For example, during the intermediate hours, signals 121, 221, 321 and 421 are produced respectively for the first, second, third and fourth areas. This relationship between each area and the traffic demand signal issued for that particular area may be varied as desired according to the condition of the building provided with the elevator system involved. Also, it is apparent that the whole service floors may be divided into any number of areas as desired instead of four.

The present invention is of course not limited to the case in which a l0-storied building is served with three elevator cars, as already explained. It should also be noted that according to the invention the forward extension of service zone is limited by applying to AND 

1. An elevator control device for an elevator system having a multiplicity of elevator cars serving a multiplicity of floors, said control device comprising means for determining the service zone of each car at each moment, the car being able to respond only to a hall call from floors within the zone, means for transmitting a hall call generated from a floor to a car whose service zone includes said floor, means for setting the maximum size of the service zone of each car, and means for limiting the forward extent of said service zone in response to the operation of said means for setting the maximum size of service zone.
 2. An elevator control device according to claim 1, in which said means for setting the maximum size of service zone provides a fixed maximum size.
 3. An elevator control device according to claim 1, in which said means for setting the maximum size of service zone includes means for adjusting the maximum size.
 4. An elevatoR control device according to claim 3, in which said means for adjusting the maximum size of service zone includes means for selecting one out of a plurality of preset maximum sizes of service zone.
 5. An elevator control device according to claim 4, in which said means for selecting the plurality of preset maximum sizes of service zone selects smaller maximum sizes for a car travelling up than those for a car travelling down.
 6. An elevator control device according to claim 4, in which said means for selecting the plurality of preset maximum sizes of service zone selects smaller maximum sizes for a car travelling down than those for a car travelling up.
 7. An elevator control device according to claim 4, in which said means for selecting the plurality of preset maximum sizes of service zone selects smaller maximum sizes for a car travelling toward a specific floor than those for a car travelling away from said specific floor.
 8. An elevator control device according to claim 3 further comprising means for detecting the operating condition of each car, and controlling means for controlling said means adjusting the maximum size of the service zone in accordance with the output from said means for detecting the operating condition.
 9. An elevator control device according to claim 8, in which said means for detecting the operating condition of each car includes means for detecting the traffic demand of each car.
 10. An elevator control device according to claim 9, in which said means for detecting the traffic demand for each car includes means for detecting the number of floors expected to be served by the car.
 11. An elevator control device according to claim 9, in which said control means controls said means for adjusting the maximum size of service zone so that the maximum size of service zone is reduced when the output from said means for detecting the traffic demand for said car exceeds a predetermined level.
 12. An elevator control device according to claim 8, in which said means for detecting the operating condition includes means for detecting the interval between a car and the succeeding car.
 13. An elevator control device according to claim 12, in which said control means controls said means for adjusting the maximum size of the service zone so that the maximum size of service zone is reduced when the output from said means for detecting the interval between said car and the succeeding car is smaller than a predetermined level.
 14. An elevator control device according to claim 8, in which said means for detecting the operating condition includes said means for detecting traffic demand for said car and said means for detecting the interval between said car and the succeeding car.
 15. An elevator control device according to claim 14, further comprising means for subtracting the output of said means for detecting the interval between said car and the succeeding car from the output of said means for detecting the traffic demand for said car, and in which said control means controls said means for adjusting the maximum size of the service zone so that the maximum size of service zone is reduced when the output from said means for subtraction is larger than a predetermined level.
 16. An elevator control device according to claim 8, in which said means for detecting the operating condition includes means for detecting the net load in the car.
 17. An elevator control device according to claim 16, in which said control means controls said means for adjusting the maximum size of the service zone so that the maximum size of service zone is reduced when the output of said means for detecting the net load in the car exceeds a predetermined level.
 18. An elevator control device according to claim 3, further comprising means for detecting the traffic condition of a plurality of cars, means for calculating the average traffic demand on the basis of the outputs from said means for detecting the traffic condition of tHe plurality of cars, and means for comparing the output of said means for calculating the average traffic demand with the traffic demand for a car, wherein said control means controls said means for adjusting the maximum size of the service zone of said car in accordance with the output from said means for comparison.
 19. An elevator control device according to claim 3, further comprising means for detecting the traffic demand in each of a plurality of areas into which said multiplicity of floors are divided, wherein said control means controls said means for adjusting the maximum size of the service zone of each car located in each area in accordance with the output from said means for detecting the traffic demand.
 20. An elevator control device according to claim 19, further comprising means for comparing the output from said means for detecting the traffic demand of each of said areas with the output from means for calculating the average demand of said plurality of areas, wherein said control means controls said means for adjusting the maximum size of the service zone of each car located in each area in accordance with the output from said means for comparison.
 21. An elevator control device according to claim 19, wherein said control means controls said means for adjusting the maximum size of the service zone so that said maximum size of the service zone of said car is reduced when the output from said means for detecting the traffic demand of each area is smaller than a predetermined level.
 22. An elevator control device according to claim 1, in which said means for setting includes means for determining the maximum size of the service zone of a car on the basis of the distance from the actual position of said car.
 23. An elevator control device according to claim 1, in which said means for setting includes means for determining the maximum size of the service zone of a car on the basis of the distance from the provisional position of said car.
 24. An elevator control device according to claim 1, further comprising means for detecting generation of a hall call and acertaining that the floor from which said hall call is generated is included in the service zone of one of the cars, and means for informing said floor of the expected service of said car upon energization of said means for detecting the generation of a hall call.
 25. An elevator control device according to claim 1, further comprising means for de-energizing said means for limiting the forward extension of the service zone under predetermined conditions. 